System for pulverizing and grading material.



No. 7|o,6o4. Patented oct. 7, |902. w. s. osBonNE a. E. c. BRYANT. SYSTEM FR PULVERZING AND GRADlNG MATERIAL.

A lic pp atxon lsd Dec. 17, 1900.)

(In Nudel.) 2 Sheets-*Sheet L Patented Oct. 7, IB02. W. S. OSBORNE & E. C. BRYANT.

SYSTEM FOR PULVERIZING AND GRADING MATERIAL.

(Application filed Dec. 17, 19011)' (No Model.)

2 Sheets-'Sheet 2.

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UNTTED STATES PATENT OFFICE.

VILLIAM S. OSBORNF. AND ELVIN C. BRYANT, OF ST. LOUIS, MISSOURI.

SYSTEM FOR PULVERlZING AND GRADING MATERlAL.

SPECIFICATION forming part of Letters Patent No. 710,604, dated October 7, 1902.

Application tiled December 1'7, 1900. Serial No. 40|l77- (N0 model-l To fol/ whom, it ntrtg/ concern.

Be it known that we, WILLIAM S. OsnoRNE and ELWIN C. BRYANT, citizens of the United States, residing at the city of St. Louis, in the State of Missouri, have inventeda certain new and useful Improvement in Systems for Pulverizing and Grading Material, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part of this specication, in which- Figure l is a View illustrating the apparatus employed in our improved system for pnlverizing and grading material. Fig. 2 is a top plan view, part-ly in section, of a grader which initially operates upon the pulverized material. Fig. 3 is a vertical sectional view through said grader. Fig. e is a top plan view, partly in section, ofthe separator. Fig. 5 is a vertical sectional view of the separator. Fig. G is a top plan view, partly in section, ot' the auxiliary separator; and Fig. Tis a vertical sectional view through said auxiliary separator.

This invention relates toa new and useful improvementiu a system for pulverizing and grading material, the object being to separate the particles of pulverized material from the air t'or the purpose of collecting the same, either in the form ot' finished product or as tailings to be returned to the grinding or pulverizing machine.

One of the objects of our present invention is to employ far as possible the same air as a vehicle for carrying the particles of material from the reducing-machine to the separating apparatus, said air after being freed from said particles being returned to the machine to be used again. In this manner the small particles of material, which are so finely divided and so light as to be practically uncollectible, are kept in the system and by being repeatedly subjected toa separating action will eventually take the path of the iinished product.

lVith this object in view our invention consists in a system for pnlverizing and grading or separating material, such as will hereinafter be described, and afterward pointed ont in the claims.

In the drawings, A indicates a machine for reducing material to a finely-divided state, the material to be reduced being fed into said, machine through a closed hopper containing a feeding apparatus a. This reducing-machine may be of any desirable construction, and we have not, therefore, shown the details of the same in the drawings.

B indicates a spout leading from the top of the machine, into which the reduced material from the machine is received.

b is a valve iu the spout B.

The spout B leadsinto what we have designated as a grader C, the details of which are shown in Figs. 2 and This grader preferable consists of an octagonal casing having a conical lower portion discharging into a spout D, which spout connects with the feed end of the mashine and is provided with a valve d. The top of the grader is closed byv a suitable cover.

E indicates a deflectorsecured to the grader in advance of the inlet-opening, said detlector being attached at one side and to the top of the grader, an opening or space being provided at the opposite side and bottom of said dei'lector for the passage of the dust-laden air. wish to be understood as meaning the air coming from the grinding-machine which serves as a vehicle to carry the particles ot' reduced material in suspension. dust-laden air is introduced into the grader C, it strikes the deliector E and is caused to take other than a straight path, being directed downwardly and to one side, so that the heavier particles will fall and the lighter particles will be'carried by the air to and through the escape-opening. Where two grinding-machines discharge into a single grader, we prefer to employ a pipe B and a dei'lector E, which operate in substantially the same way as above described. However, in this description We will assume that the pipe B' is a blind pipe having a cap provided at its end.

F indicates a dischargepipe leading from the head of the grader opposite the inlet-pipe B, said pipe F connecting with the eye of a fan G. A suitable valvef is arranged in the pipe F.

H indicates a pipe leading from the fau G In speaking of the dust-laden air we.

When this IOO into the head of a separator I. Before proceeding with a detailed description of this separator We will brieiiy describe the operation of the grader C. In using the term grader in connection with this construction we do so, primarily, to distinguish this part of our apparatus from the separator. The purpose of this so-called grader is to initially grade the pulverulent material, returning the large particles, called tailings, back to the grinding-machine to be reduced and permitting the particles of suiiicient tineness to pass on beyond the grader. In other words,thisso-calledgraderservesasascreen in that by regulating the valves in the spout of the exhaust-fan it is possible to cause material of varying degrees of iineness to be passed therethrough, say, up to a certain mesh, those particles of material exceeding in size the desired mesh being returned to the machine for regrinding or to a suitable receptacle as finished product. It will be observed that the grinding-machine operating in a closed system Will thoroughly reduce the material. The vacuum in spout B can be regulated by the valve b. The dust-laden air entering the grader will be deflected laterally and downwardly, the tortuous passage it is compelled to follow resulting in the precipitation of heavier particles of material into the pipe D, which connects with the feed end of the pulverizer. rlhe outlet-pipe F being connected with the eye of an exhaust-fan will have a constant tendency to draw and exhaust all the air and its carried particlesV of material through the grader. The amount of air admit-ted to the grader is controlled by the valves b and d, the available area through which said air is drawn into the fan being controlled by the valvef.

Itis well known that particles of material held in suspension in air rely upon the air resistance for their bouyancy and that if said particles of material were placed in a vacuumchamber wherein the air would offer no resistance to the action of gravity said particles of material would be practically dead, so far as their icating capacity is concerned. We take advantage of this natural law in effecting the grading action in the chamber C by exhausting the air from said chamber and creating a partial vacuum therein, so as to take away from the particles of material the sustaining properties of the air, rendering them more susceptible to the action of gravity. Being introduced into a chamber from which the air is being constantly exhausted and wherein there exists a partial vacuum and being compelled to take a tortuous passage at the time of introduction into said chamber, the particles of material will immediately become more susceptible to the action of gravity when they reach the gradingchamber, and the heavier particles will fall and the lighter particles will be drawn into the pipe F to the exhaust-fan. By regulating the valve d the ineness of the particles entering the pipe F can be controlled. If said valve is closed or nearly closed, it follows that there is no upward circulation of air through the pipe D. Therefore the heavier particles are not resisted in their descent, and a more finely-divided product Will thus pass through the pipe F. If, on the other hand, the valve d is open to permit an upward circulation of air therethrough, the particles of material meeting with this resistance are held in suspension by the air passing upwardly through the pipe D, and consequently the material passing through pipeF is of acoarser quality. The regulation of valve b is such that the opening controlled thereby is about sufficient to take care of the capacity of the grinding-machine without admitting an excess quantity of air at this point; but of course it will be understood that the valve b being open full will affect the degree of fineness ot' the particles of material passing through the pipe F. However, it is not intended t0 use the valve b for the purpose of accomplishing this, said valve being designed, primarily, to cont-rol the exit-opening from the grindingmachine, and thus goesmore to accommodating the capacity of said machine than to controlling the quality of ground material passing beyond the bolter. The valve fis adjustable `to regulate the discharge-opening from the grader according to the capacity of the fan, and While the opening controlled by this Valve will aifect the quality of material passing therethrough said valve is not intended to be used for this purpose, we preferring to rely rather on the valve d, which is not only more accessible, but, depending upon conditions, can be manipulated as occasion requires-as, for instance, an excess ot' heavy particles falling into the pipe D would require the valve d to be opened to a greater extent, while a scarcity of material in pipe D would require that the valve d be closed. The accessibility of valve CZ and its ease of manipulation is of advantage in the event of an irregular feed of material into the grinding-machine. If the material to be ground is not regularly fed and there is no regulation of valve CZ, it follows that a variation in the quality of the product will result, which is undesirable. We do not claim the details of this grader in this application, as the same forms the subject-matter of an application filed contemporaneously herewith on December 17, 1900, Serial No. 40,176, the same being designated as Case B.

The pipe H being the discharge-pipe from the exhaust suction-fau G leads into the head of a separator I, the details of construction of which are shown in Figs. Lland 5. Referring now to these figures, it will be seen that the discharge-pipe enters the head of the separator on a parallel line with one of the sides of the Octagon, and the dust-laden air is forced to pass in a downward direction by the inclined defiecting-pipes It', leading from the head to the main body of the machine,

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the particles of material being whirled around and by centrifugal :force caused to hug the conical lower` portion 0f the separator until they enter-the discharge-spout J. This discharge-spout is provided with a valve j for well-understood reasons. In Fig. l we have shown scales upon which is arranged a bag for receiving the material from the dischargespout J. The top of this separator is closed to the exterior, but receives a pipe K, which extends some distance down into the separator-chamber, the introduced end of said pipe being surrounded by the inner casing of the head 7c, whose lower end affords a point of attachment for the various inclined deflecting-pipes t'. As stated before, the dust-laden air enters the chamber of this separator, and centrifugal force causes the particles of dust or most of them to hug the walls of the chamber until finally they are deposited in the discharge-spout J. In some classes of material, where it is possible to meisten the particles of dust in the air and to the eXtent that they absorb such moisture they become heavier and are more readily deposited in the discharge-spout, we introduce a steam-pipe L, having a jet at its ends, which jet throws the steam into the head of the separator at the point of introduction of the dust-laden air. We may also employ a perforated steampipe M near the lower end of the hood and beneath the inclined defiecting-pipes t' for the purpose of introducing steam into the separatingchamber at a point where the dust-laden air passes from the contracted discharge-mouth of the head into the larger conical chamber. We do not claim the details of this separator in this application, as the same forms the subject-matter of an application filed contemporaneously herewith on December 17, 1900, Serial No. 40,178, and designated Case C. Any finely-divided particles of material in the separator which are not deposited in the discharge-spout J will pass upwardly through the pipe K, and instead of permitting said particles to escape to the exterior we prefer to lead said pipe K into an auxiliary collector N, the details of which are shown in Figs. 6 and 7. A deflector-plate n is used in advance of the pipe K, so as to impart a whirling motion to the incoming dust-laden air, causing the particles thereof to be deposited in the dischargespout G, while the purified air escapes into the atmosphere through a pipe P. This pipe P extends down into the head of the auxiliary separator N some distance, as shown in Fig. 7. 'lo prevent the particles of material deposited in the pipe O from being lost and to avoid making special provision to receive the same, we connect the lower end of said pipe O directly with the pipe F, leading into the eye of the suction-fan, so that the particles of material in pipe O are drawn into pipe F and forced by the fan G back into the separator I. This pipe O has a depending portion o, which serves as a pocket or chamber for the collection of any water of condensation.

Of course it is obvious that in connection with some materials steam cannot be used, while in others it is not only permissible to use steam, but it is highly advantageous to do so.

lt will be observed that with respect to the system above described the same is what might be termed a closed system-that is, substantially the same air is used over and over again-the pipe P being the only communication between the system and the eX- terior. However, this pipe is located at such distance from the means for circulating the air that it serves very well the purpose of a vent, supplying the air needed in the system upon the rareication at any point outside of the grader, and in the event that there is a surplus of air in the system the vent P will provide means of escape therefor.

Our improved collector and separator can be used with various material-in fact, in connection with all materials which are reduced to a powdered formwith relation to some of which it may be possible to use water in addition to steam, while others will have to be treated dry, as before stated.

It will be obvious that instead of connecting the spout D with the feed end of the pulverizer, whereby the tailings are returned'to the machine, said spout can be led olf into a suitable receptacle for collecting said tailings. Such an arrangement will be employed Where it is desired to collect granulated material and separate the dust therefrom.

ln pulverizing-machines employing revolving beaters we have observed in actual practice that the blows of the beaters on the material to be pulverized will effect the greatest pulverization, and if the material is left in the machine it will soon assume the speed of the beaters, so that the subsequent reduction thereof is carried on by friction. In our system instead of permitting the particles of material acted upon by the beaters to be carried around in the machine and worn out by friction we create a suction upon the machine at the discharge end thereof (opposite the feed end) and endeavor to take all the material from the machine whether or not said material is reduced to a sufficient degree of lineness. By doing this the capacity of the machine is greatly increased. These particles of material, both large and small, are drawn into the grader and caused to take a tortuous path. The vacuum in the grader being greatest at the lower end thereof will effect a quick separation of the heavier from the finer particles7 said finer particles going off through the outlet-pipe F, which is of larger diameter, andinto the eye of the exhaust-fan. The polygonal shape ofthe gradershown in the drawings lends itself to a ready separation of the particles of material by the formation of eddies in the corners thereof, in addition to which the sharp turn the dust-laden air is IOO IIO

compelled to take in passing under and around the detiector-plate creates eddies in the partial vacuum behind said plate, which greatly assists in the separation. The heavier particles, in the form of tailings, falling into the discharge-spout at the lower end of the grader pass into the feed end of the machine, the valve (l being so regulated as to prevent the inrush of air, which might reduce the vacuum in the bottom of the grader. These tailings being thus returned to the machine are again subjected to the action of the beaters and pulverized, or partially so, said comminuted tailings again passing up through the discharge-pipe B and into the grader, and so on, this cycle of operations continuing until the material is reduced to a degree of fineness capable of being drawn out through the outlet-pipe F. Thus it will be seen that friction is not relied upon to reduce the material in the pulverizer, the actual blows of the beaters more quickly and readily reducing the material, while the suction on the mill keeps it free and clean and permits of the beaters acting upon a greater quantity of material than they could otherwise act upon without choking the machine. As the dust-laden air is forced beyond the exhaust-fan it enters the enlarged head of the separator through the inlet-pipe thereof, which is tangentially arranged, so that the airis forced to move in one direction around said head. Where the material is capable of being moistened in the head, this unidirectional movement permits of the dust-laden air remaining for a longer period in the head, so that the moisture will have an opportunity of becoming absorbed by the particles of material. When the dustladen air is deiiected downwardly, it does not lose any of its speed, and the polygonal shape of the casing of the separator enables the formation of small eddiesin the corners thereof, which assist in freeing the air from its carried particles. It will also be seen that the air entering the pipe K is in a whirling state, which continues until the air is discharged into the auxiliary separator. In passing through the pipe K, which pipe is circular, the axis of the whirling air follows the axis of the pipe, so that in entering the auxiliary separator any particles of material carried by the air will spread until their direction of movement is changed by the curved deiiector plate in the auxiliary separator. The restraint thus placed upon the air and its carried particles produce what might be termed a break, in that the air is forced to suddenly change its direction and in so doing more readily yields its carried particles and permits them to fall into the discharge-pipe leading from this auxiliary separator. Of course after breaking the air is given a circular motion in the auxiliary separator and by reason of the polygonal shape of said separator the eddies formed in the corners assist in freeing the air of its particles, centrifugal force being relied upon as the principal element in this separation.

We are aware that minor changes in the arrangement, construction, and combination of the several parts of our device can be made and substituted for those herein shown and described without in the least departing from the nature and principle of our invention.

Having thus described our invention, what we claim, and desire to secure by Letters Patent, is-

l. ln a system for pulverizing and grading material, the combination with a machine for reducing the material to powdered form, a grader C, a spout leading from the reducingmachine into the grader, a spout D connecting said grader with the feed end of said machine, a pipe F, a fan Gr associated with the pipe F, a separator I, a pipe leading from the fan into the separator, a discharge-pipeJfor the separator, an auxiliary separator N opening to the atmosphere, a pipe K between the separators N and I, and a discharge-spout O leading from said auxiliary separator and connecting with the pipe F; substantially as described.

2. In a system for pulverizing and grading material, the combination with a machine for reducing the material to powdered form, ofa grader for receiving the product thereof, an exhaust-fan connected to said grader, a separator for receiving the graded material under pressure, a discharge-spout leading from said separator, a valve in said discharge-spout, a pipe leading from said separator into an auxiliary separator, a pipe P leading from said auxiliary separator, a discharge-spout O leading from said auxiliary separator back to the exhaust-fan and a valve in said last-mentioned discharge-spout; substantially as described.

3. In a system for pulverizing and grading material, the combination with a machine for reducing material to powdered form, of a grader for receiving the product of said machine, a suction-fan for rarefying the air in said grader and discharging the dust-laden air under pressure into a separator, an auxiliary separator connected with said first-mentioned separator, a discharge-spout leading from said auxiliary separator and connecting with the discharge-fan, steam-pipes for admitting steam into the primary separator, and a pocket or chamber connecting with the discharge-spout of the auxiliary separator for collecting the water of condensation therefrom; substantially as described.

et. In a system for pulverizing and grading material, the combination with the machine for reducing the material to powdered form, of a pipe leading from said machine, a grader into which said pipe leads, a discharge-pipe leading from the grader into the eye of an exhaust fan, another discharge pipe leading from said grader for returning the heavier particles of material back to the feed end of IOO I'IO

the pulverizing-inachine, an exhaust-.fan for creating a suction upon the machine and a Vacuum in said grader, a separator into which the dust-laden air is forced from the exhaustfan, a pipe leading from said separator for carrying off the excess air, said air entering said pipe in a whirling state, an auxiliary separator for receiving the whirling air from said pipe, and means in said auxiliary separator for causing the air to break and change its direction; substantially as described.

5. An apparatus of the character described, comprising a reducing-machine, a grader C adjacent thereto, a pipe B leading from the reducing-1nachine to the grader, a pipe D leading from the lower end of the grader back to the reducing-machine, a separator l, pipes F and H intermediate of the separator and grader and communicating with the same, and a fan associated with the adjacent ends of the pipes F and H and adapted to draw material from the reducing-machine through the pipe B and grader C and force the same into the separator I; substantially as described.

G. An apparatus of the character described comprising a reducing-machine A having a receiving-hopper at one end thereof, a grader C supported above the reducing-machine, a pipe B leading from the reducing-machine upwardlyinto the upper portion of the grader, a valve in said pipe, a pipe D leading from the lower end of the grader downwardly into the hopper of the reducing-machine, a valve in said last-mentioned pipe, and an exhaust device associated with the upper end of the grader at a point remote from the discharge of the pipe B thereinto and adapted to draw material from the reducing-machine through the pipe B and grader C; substantially as described.

7. An apparatus of the character described comprising a reducing-machine A having a receiving-hopper at one end, a grader C adjacent to said reducing-machine, a pipe B leading from the top of the reducing-machine into one side of the grader C, a suction device at the opposite side of the grader and adapted to draw material from the reducing-machine through the pipe B and grader C, and a valved pipe leading from the bottom ofthe grader into the receiving-hopper of the reducingmachine; substantially as described.

8. An apparatus of the character described comprising a reducing-machine A, a grader C adjacent to said reducing-machine, a pipe B leading from the reducing-machine into the upper portion of the grader, a pipe D leading from the lower portion of the grader back to the reducing-machine, a valve in said pipe D, and a suction device associated with the upper portion of the grader, at a point remote from the discharge of the pipe B thereinto and adapted to draw material from the reducing-machine through the pipe B and grader C; substantially as described.

9, An apparatus of the character described comprising a reducing-machine, a grader, a pipe connecting the reducing-machine with the grader, a separator I, an exhaust-fan associated with the grader for rarefying the air therein and forcing the dust-laden air into the separator, an auxiliary separator N, a communication between the two separators, and a pipe O leading from the auxiliary separator back to the exhaust-fan; substantially as described.

l0. An apparatus of the character described comprising a reducing-machine, a separator l, an exhaust-fan for withdrawing material from the reducing-machine and forcing the same into said separator, an auxiliary separator N, a communication between the two separators, and a pipe O leading from the auxiliary separator back to the exhaust-fan; substantially as described.

In testimony whereof we hereunto afx our signatures, inthe presence of two witnesses, this 14th day of December, 1900.

WILLAM S. OSBORNE. ELWIN C. BRYANT.

lVitnesses:

F. It. CORNWALL, WM. Il. SCOTT. 

